1 882.] The Reptiles of the American Eocene. gycj 



as well ask, how can a crystal grow without sensation. Nor has 

 that great naturalist failed to perceive these extreme consequences 

 of this extension of the biological jurisdiction, for he seeks to 

 escape them only by pushing it still farther, and proclaiming the 

 animation of all material atoms, even of the lowest orders — du 

 Atom-Seek. It seems far simpler, as well as more correct, to 

 recognize in protoplasm a true chemical substance, but one whose 

 properties constitute the fundamental element of life. 



Such a conclusion is no longer the bold speculation that it 

 would have been pronounced a kw years ago, and this paper 

 could not be more fittingly concluded than with the words of 

 Professor O. C. Marsh, uttered in 1877, that " if we are permitted 

 to continue in imagination the rapidly converging lines of re- 

 search pursued to-day, they seem to meet at the point where or- 

 ganic and inorganic nature become one. That this point will yet 

 be reached, I cannot doubt." 



THE REPTILES OF THE AMERICAN EOCENE. 



DEMAINS ofBairackia are rare in North American formations 

 ** later than the Permian. There are two or three species of 

 Stegocephali known from the Trias, above which formation that 

 order is not known to extend in any country. No Batrachians 

 have been obtained from the Jurassic or Cretaceous systems ex- 

 cepting from the top of the latter, in the Laramie. Here occur 

 the salamandrine genera Scapherpeton and Hemitrypus Cope. A 

 single specimen of a frog from the Eocene is mentioned below, 

 and then we miss them until the Loup Fork or Upper Miocene, 

 where Atutr'a and salamanders have been found. 



The vertebral column and part of the cranium of a probably 

 incompletely developed tailless Batrachian, were procured by Dr. 

 F. V. Hayden, from the fish shales of the Green River epoch, 

 from near Green River City, Wyoming. They are not sufficiently 

 characteristic to enable me to determine the relation of the species 

 to known forms. It is the oldest of the order Anura yet discov- 

 ered, the fossil remains of the known extinct species having been 

 derived from the Miocene and later formations of Europe. 



The Eocene period, was, of the divisions of the Tertiary, the 



